Aftermarket stereo? That can be a problem. You might want to make sure you are not drawing too much power, and that it isn't getting its signal from somewhere stupid.

BTW, no start after a wash isn't terribly uncommon.

Your computer will open and close the ICV in an attempt to stabilize the idle. By unhooking it, you remove the computers ability to control the amount of idle air coming into the engine.
As such, your computer probably thinks your idle speed is too low.

Does anybody know how the ECU measures idle speed? That could be your trouble.

__________________
I am blessed/cursed with these cars:

BMW 318iS 1991
BMW 325iS 1988
Volvo 740 Turbo Wagon 1992

Quote of the week:

"This chemical is known to cause Birth Defects in California."

Poor Californians, they are always getting the short end of it, and now this?